JPH0721947A - Cathode-ray tube having symmetrical anode potential - Google Patents

Abstract

PURPOSE: To prevent the generation of a nonuniform voltage distribution in a conductive layer inside a cathode-ray tube by installing a couple of anode buttons in the mutual symmetry position on the outer surface of a funnel of a cathode-ray tube. CONSTITUTION: A face panel 14 coated with a fluorescent material 12 on an inner surface, a neck 16 located opposing the panel, a funnel 18 which forms a valve integrally connecting the face panel with the neck, and an electron gun installed inside the neck are provided. The funnel 18 has a conductive layer 34 which forms an electric passage which supplies an anode voltage to an inside surface. And a couple of anode buttons 32, 32a are installed and penetrated at the mutually symmetrical positions outside the funnel 18, being electrically connected with the inner conductive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube having a symmetrical anode potential in order to improve luminance unevenness on the screen in the vertical and horizontal directions.

[0002]

2. Description of the Related Art FIG. 3 shows, for example, US Pat.
No. 8,477 and the patent No. 4,638,213
1 shows a general color image cathode ray tube of the accompanying drawings disclosed in the specification.

The cathode ray tube 10 has a face panel 14 having a phosphor 12 coated on the inner surface thereof, a neck 16 facing the face panel 14, and the face panel 14 and the neck 16 integrally connected to form a bulb. It is formed by an electron gun mounted inside the funnel 18 and the neck 16 to be formed.

The electron gun of FIG. 3 is a typical bipotential type.

The above-mentioned type of electron gun comprises a cathode 22 having a heater 20, a plate-shaped control electrode 24, a screen electrode 26, a cup-shaped focus electrode 28 and a high voltage electrode 30 to which an anode voltage is applied. ing.

On one side of the outer periphery of the funnel 18, an anode button 32 penetrates the funnel 18 and is electrically connected to a conductive layer 34 on the inner peripheral surface.

FIG. 4 shows a mounting structure of the anode button 32 attached to the funnel 18.

The anode button 32 mounted through the funnel 18 has an inner surface of the funnel 18 electrically connected to the conductive layer 34 via a metal strip 36.

The conductive layer 34 is coated with colloidal graphite, and the coating range is the phosphor 1 shown in FIG.
2 and a shadow mask 38 disposed adjacent thereto, and a range that can be electrically contacted with the snubber 40 that provides an electrical path from the conductive layer 34 to the high voltage electrode 30 of the electron gun.

A predetermined voltage is applied to each electrode of the ordinary cathode ray tube shown in FIG. 3 through each stem lead 42 extending through the stem of the neck 16 to the outside.
Specifically, the cathode 22 is 200 to 400 V, the control electrode 24 is 0 to 1 KV, and the screen electrode 26 is 0 to 1 K.
V, focus electrode 28 is 1 to 10 KV, high voltage electrode 3
0 is in the range of 5-35 KV. Here, the high voltage electrode 3
The voltage applied to 0 is the same as the anode voltage.

The thermoelectrons emitted from the cathode 22 by the operation of the heater 20 are controlled by the control electrode 24 and the screen electrode 2.
6, an image is formed by colliding with the phosphor 12 as an electron beam while passing through the focus electrode 28 and the high voltage electrode 30.

[0012]

As described above, as a result of the operation of the electron gun, the face panel 14 on which an image is formed has a local brightness difference.

FIG. 5 and FIG. 6 show measurement results relating to the luminance distribution on the screen in two general 29-inch color image cathode ray tubes selected by a random method.

On the screen showing the brightness, the numbers are the brightness measurement values whose unit is lux, and the numbers in parentheses are the proportional values on the peripheral side when the brightness at the center of the screen is 100.

Further, in the screen showing the landing and stripe width, the numeral is a value obtained by measuring the stripe width of the fluorescent pattern whose unit is lux, and is shown together with A,
In order to make it easier to understand, B, C, and D are based on the landing state of the central portion, and the mislanding on the peripheral side to this is displayed by grade.

In the drawings, it can be seen that the luminance of the symmetrical portion about the center of the screen is extremely uneven.

The brightness of the cathode ray tube is determined by the material and coating state of the fluorescent pattern, the voltage distribution inside the cathode ray tube, the stripe width, and the landing state of the electron beam.

Here, assuming that the fluorescent patterns are in the same state, the factors that greatly affect the luminance of the cathode ray tube are the voltage distribution and the landing state of the electron beam.
And stripe width is mentioned.

As a result of inspecting the landing condition and the stripe width of the cathode ray tube to be measured, it was found that the relevant items do not include the cause of the uneven brightness.

Therefore, it can be assumed that the main cause of the non-uniformity of the brightness observed on the screen of the cathode ray tube is the problem of the voltage distribution.

However, since it is virtually impossible to measure the voltage distribution on the inside of the cathode ray tube, there is no way to directly prove the above assumption.

However, when the measured luminance values of the cathode ray tube are divided into parts, it can be inferred from the fact that the surface on which the anode button 32 is attached has a higher value than its symmetrical surface. It can be inferred that the voltage distribution inside the cathode ray tube has a large effect on the brightness.

In other words, the conductive layer 34 adjacent to the anode button 32 has a more dense charge than the conductive layer 34 located at a symmetrical position far away from the anode button 32, and as a result, the voltage distribution is nonuniform. It is considered that the brightness is affected and the brightness is affected.

Such an assumption becomes even clearer from the measurement result of the influence of the earth magnetic field of the cathode ray tube to be measured.

FIG. 7 shows that when the cathode ray tube to be measured according to FIG. 5 is oriented in one of north, south, east, west, and again after it is placed in the east and demagnetized, the direction is changed to the west (E / W), and after degaussing in the north and changing the direction to the south (N / S), the amount of beam movement due to the amount of change in the horizontal magnetic field was measured for each part. It shows the difference in the amount of movement.

As a result of the measurement, the symmetrical parts on the peripheral side at the center of the screen show a great difference. Such a phenomenon is also found in the beam movement amount according to the change of the vertical magnetic field due to the earth magnetic field, as shown in FIG. can do. It is considered that the cause is that the electric charge on the peripheral side of the anode button 32 becomes denser than the symmetrical portion and is further affected by the earth magnetic field.

Therefore, an object of the present invention is to make the conductive layer inside the cathode ray tube have a uniform anode charge based on the above-mentioned assumption, so that the phenomenon of non-uniform brightness on the screen does not occur. Is to provide.

Another object of the present invention is to mount a pair of anode buttons on the outer peripheral surface of the funnel of the cathode ray tube at symmetrical positions so that a non-uniform voltage distribution does not occur in the conductive layer inside the cathode ray tube. Is to provide.

[0029]

To achieve the above object, a cathode ray tube having a symmetrical anode potential according to the present invention is a face panel having an inner surface coated with a phosphor, a neck opposed to the panel, and these faces. A funnel forming a bulb by integrally connecting the panel and the neck, and an electron gun attached to the inside of the neck, the funnel being a conductive layer forming an electric path to which an anode voltage can be supplied on an inner surface thereof. In addition, a pair of anode buttons are attached and penetrated outside the funnel at positions symmetrical to each other, and are electrically connected to the inner conductive layer.

[0030]

According to the present invention, since the pair of anode buttons are provided outside the funnel at positions symmetrical to each other, the phenomenon of nonuniform brightness on the screen does not occur, and the conductivity inside the cathode ray tube is prevented. Inhomogeneous voltage distribution across the layers also no longer occurs.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS.

The cathode ray tube 10 shown in FIG. 1 is a face panel 14 having a phosphor 12 coated on its inner surface.
16 and a face panel 14 facing each other
And a neck 16 are integrally connected to each other to form a bulb, and a funnel 18 and an electron gun mounted inside the neck 16.

In this cathode ray tube 10, the electron gun is a bipotential type which is composed of a cathode 22 having a heater 20, a control electrode 24, a screen electrode 26, a focus electrode 28, and a high voltage electrode 30 to which an anode voltage is applied. It is said that.

On the outer periphery of the funnel 18, a pair of anode buttons 32, 32a are arranged symmetrically with respect to each other.
And is attached in a state of being electrically connected to the conductive layer 34 on the inner peripheral surface.

The pair of anode buttons 32, 32a may be arranged at any position on the outer peripheral surface of the funnel 18 as long as they can be attached at symmetrical points on the outer peripheral surface of the funnel 18.

As a result, the conductive layer 34 becomes the funnel 18
There are two voltage application passages passing through a pair of anode buttons 32 and 32a penetratingly attached to the outer circumference of the anode.

The conductive layer 34 is coated with colloidal graphite, and its coating range is the phosphor 12, the shadow mask 38 disposed adjacent to the phosphor 12, and the conductive layer 34.
Is limited to the range in which the high voltage electrode 30 of the electron gun can be electrically connected to the snubber 40 that provides an electrical path.

A predetermined voltage is applied to each electrode constituting the electron gun through each stem lead 42 which extends through the stem of the neck 16 to the outside. Specifically, the cathode 22 is 200 to 400 V, and the control electrode 24 is 0 to 1
KV, the screen electrode 26 is 0 to 1 KV, the focus electrode 28 is 1 to 10 KV, and the high voltage electrode 30 is 5 to 35 KV.
Is the range. Here, the voltage applied to the high voltage electrode 30 is the same as the anode voltage.

The thermoelectrons emitted from the cathode 22 by the operation of the heater 20 are controlled by the control electrode 24 and the screen electrode 2.
6, an image is formed by colliding with the phosphor 12 as an electron beam while passing through the focus electrode 28 and the high voltage electrode 30.

In this process, the conductive layer 34 applied to the inner peripheral surface of the cathode ray tube 10 is applied with a high potential anode voltage through the pair of anode buttons 32 and 32a arranged symmetrically to each other. Therefore, the voltage distribution due to the charges latent in the conductive layer 34 becomes symmetrical on the inner peripheral surface of the funnel 18 around the pair of anode buttons 32, 32a.

As the voltage distribution of the conductive layer 34 from the inside of the cathode ray tube 10 becomes symmetrical, the result of measuring the luminance distribution of the screen affected by this is as shown in FIG. It showed what makes up.

The present invention is not limited to the above embodiment, but can be modified as necessary.

[0043]

As described above, since the cathode ray tube having the symmetrical anode potential of the present invention is constructed and operates, the image quality of the peripheral portion having lower luminance than the central portion of the screen is made uniform in luminance distribution. There is an effect such as being able to be improved by a visual effect through.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of a cathode ray tube according to the present invention.

FIG. 2 is a diagram showing the luminance distribution on the screen of the cathode ray tube of the present invention.

FIG. 3 is a sectional view schematically showing the configuration of a typical conventional cathode ray tube.

FIG. 4 is a cross-sectional view of the anode button shown in FIG.

FIG. 5 is a diagram showing a cathode ray tube of the type according to FIG. 3, showing a luminance distribution on a screen, an electron beam landing and a stripe width of a randomly selected cathode ray tube to be measured.

FIG. 6 is a diagram showing a cathode ray tube of the type shown in FIG. 3, in which the luminance distribution on the screen, the electron beam landing, and the stripe width of a randomly selected cathode ray tube to be measured are shown.

FIG. 7 is a diagram showing the amount of movement of an electron beam according to changes in horizontal and vertical magnetic fields due to the earth's magnetic field in the device under test of FIG.

8 is a diagram showing the amount of movement of an electron beam in response to changes in horizontal and vertical magnetic fields due to the earth's magnetic field in the device under test of FIG.

[Explanation of symbols]

 10 Cathode Ray Tube 12 Phosphor 14 Face Panel 16 Neck 18 Funnel 32, 32a Anode Button 34 Conductive Layer

Claims (1)

[Claims] 1. A face panel (14) having an inner surface coated with a phosphor (12), a neck (16) facing the panel (14), and a face panel (14) and a neck (16). The funnel (18) includes a funnel (18) connecting the two together to form a valve, and an electron gun mounted inside the neck (16).
Has a conductive layer (34) on its inner surface that forms an electrical path through which an anode voltage can be supplied, and also has a funnel (1
8) A symmetrical anode characterized in that a pair of anode buttons (32), (32a) are attached to the outside of the above 8) at positions symmetrical to each other and electrically connected to the inner conductive layer (34). A cathode ray tube having an electric potential.